Note: Descriptions are shown in the official language in which they were submitted.
Y~17Z()63
T~A~SMISSION REVERSE~ UNIT
Backqround of the Invention
This invention relates to hydraulically assisted
transmission reverser units like those employed in off-road
vehicles.
Off-road vehicles are generally utilized at job sites remote
from a repair facility. Therefore, should a vehicle repair be
necessary, substantial vehicle down time c~n be accumulated
before a repair can be effectuated. In many cases involving
worn or defectively operating major components, it is necessary
to transport the vehicle from the job site to a distant repair
facility. A power shift transmission reverser can represent
just such a major component.
A power shift reverser includes clutch and/or brake
assemblies housed within the reverser case. The clutch and
brake assemblies are subject to wear degradation reguiring their
repair or replacement. In conventional reversers, the clutch
and brake asssembly cannot be se}viced withGut totally removing
the reverser from the vehicie and completely disassembling the
reverser unit because of access limitation. As a result, the
repair or replacement of the reverser clutch and brake assembly
represents substantial vehicle down time.
The need to remove the reverser unit from the vehicle and
disassemble the unit can also be predicated upon reassembly
1imitation. ~uring the disassembly of a conventional reverser,
it is necessary to disturb the sun pinions relative ~o the
planetary pinions of a planetary gear assembly associated with
the reverser in order to remove the clutch and/or brake
assembly. Therefore, upon reassembly, it is necessary to
reposition the sun pinions relative to the planteary pinions. A
special case is presented when the number of sun pinion teeth is
odd. In such cases, the number of relative locations in which
the sun pinion will mesh properly with respective to the
planetary pinions are limited, often re~uiring manipulation of
the planetary pinion carrier to achieve a proper mesh.
Summary of the Invention
It is therefore an objective of the present invention to
present a power shift reverser unit with serviceability
properties allowing the removal of the clutch and/or brake
assemblies within the reverser without the necessity for total
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1 removal of the reverser unit from the vehicle drive train and in
conjunction therewith without re~uiring total disassembly of the
reverser unit to gain access to the clutch and/or brake
assemblies.
It is a further objective of the present invention to
present a means of removing and replacing the reverses' clutch
and/or brake assemblies without disturbing the sun and planetary
pinions of an associated planetary gear assembly.
The reverser includes a carrier having a double planetary
pinion rotatably mounted thereon. The first pinion of the
planetary is in constant mesh with a first pinion of a sun
gear. The first sun pinion is splined to the sun gear shaft.
The second pinion of the planetary is in constant mesh with a
second sun pinion which is rotatably maintained along the sun
gear shaft. The second sun pinion is in constant mesh with a
clutch drum which extends into the rear portion of the reverser
and coupled tc a reverse brake. A planetary clutch hub is
splined to the sun gear shaft and is clutchable to the clutch
drum in the rear portion of the reverser. The brake and clutch
20assemblies are located in the rear portion of the reverser such
that the rear cover can be removed whereupon the braking and
clutch assemblies can be withdrawn from the reverser housing
without the need for removing the reverser unit from a vehicle
drive train and in conjunction therewith without the need to
25further disassemble the reverse unit.
The sun shaft, which also serves as an output shaft, is
supported in a cantilever fashion by the rear cover and is
longitudinally slidable in and out of the sun pinions. The sun
shaft can, therefore, be withdrawn and reinserted central to the
30sun pinions without dislocation of the sun pinions. Further,
the sun shaft portion within the first sun pinion can experience
a degree of float such that the sun shaft can seek a concentric
alignment to the sun pinions.
The present invention offers the benefit, when associated
35with a vehicle, of allowing job site repair of the reverser
clutch and brake assembly by simply detaching the rear cover ard
slidably removing the clutch and the brake assemblies, and sun
shaft. A substitute assembly can be inserted without the need
for realigning the sun pinions.
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1 Additional benefits of the present invention will be
evidenced in the subsequent detailed description of the
preferred embodiment of the invention.
Brief Description of the Drawings
The figure is an elevated sectional view of a vehicle
reverser in accordance with the present invention.
Description of the Preferred Embodiment
Refereing to the fig~re, a housing 11 defines three cavities
13, 15, and 17. In the preferred embodiment, a conventional
torque converter, generally indicated as 19, is fixably mounted
by any conventional means to housing wall 25 in a first cavity
13. Housing wall 25, fixably mounted by any conventional means
to a formed mounting ring 26 in housing 11, divides cavity 13
from cavity 15. The torque converter 19 is splined to an input
15shaft 21 at 23. The input shaft 21 is rotatably mounted by any
conventional means in and extends through transmission wall 25.
The input shaft 21 is splined to a carrier 29 at 31 located in a
second cavity 15. The carrier 29 is rotatably supported by wall
25 at the left hand end and by a formed housing wall 33 in
20housing 11 at the right hand end by any conventional means.
Housing wall 33 divides cavity 15 from 17. The carrier 29 has
rotatably maintained thereon, by any conventional means, a
formed double planetary pinion 35 having a first and second
pinion 37 and 39, respectively. A sun gear 41 includes a sun
25gear shaft 43 extending generally co-linearly with the input
shaft 41 and at the left hand end placed aenerally central to
the carrier 29; a first sun pinion 45 splined to one end of sun
shaft 43 at 47 and in constant mesh with the first pinion 37 of
the planetary pinion 35; and, a second sun pinion 51 encircling
30the sun shaft 43 in constant mesh with second pinion 39 of
double planetary pinion 35. A portion of the sun gear shaft 43
extends beyond the sun gear 41 to serve as an output shaft. It
is observed that the planetary pinions 37 and 39 are of
different sizes, planetary pinion 37 being the larger.
To form a brake assembly 52, a clutch drum 53 has a
generally disc-like configuration having a circular collar 55
defining a hole at its center. The collar 55 is inserted into
the carrier 29 at its right-hand end and splined to sun pinion
51 at 57, the disc portion of drum 57 being parallel to and
40beyond wall 33 on the right hand side in housing cavity 17.
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~lined to the outer periphery of the drum 53 is a first and
1 second friction disc 59. Placed to each side of friction discs
59 is friction pads 61. The friction discs 61 are
longitudinally slidably mounted around a plurality of pins 63
each pin 63 having one end inserted in housing wall 33 and the
5 other end inserted in a rear cover 65 enclosing the rear portion
of housing 11. The sun shaft 43 is also rotatably mounted in
rear cover 65 and extends therethrough. Friction pads 61 are
also slidable along slots 64 in rear cover ~5O An outer
friction pad 61 slidable along pin 63 is biased by a spring 67
placed around pin 63. A brake piston 69, having a generally
ring configuration, is slidably mounted opposite to plate 61 in
a conforming cavity of the rear cover 65 and is hydraulically
actuated in a conventional manner to brake drum 53 to housing
11 .
To form a clutch assembly 70, a planetary clutch hub 71 is
splined to shaft 43 at 73 generally in housing cavity 17.
Splined to the outer periphery of clutch hub 71 are a plurality
of friction discs 75. Interspersed between friction discs 75
are friction pads 77. In the preferred embodiment, a clutch
20cover 80 is fixably mounted in a clutch drum 53 by a plurality
of bolts 82 and rotatably mounted around sun shaft 43 such that
the friction pads 77 and friction disc 75 are between clutch
drum 53 and clutch cover 80. The friction pads 77 can axially
slide in slots 84. A ring-like clutch piston 79 is slidably
25mounted opposite to the friction discs 75 and plates 77 in a
conforming cavity of clutch cover 80, the clutch piston 79 being
hydraulically actuated by any conventional meanC to clutch hub
71 to drum 53. A spring 81 biases clutch piston 79 to a release
position. The spring 81 is placed in a clutch cover sleeve 83
30between a stop member 85 and clutch piston 79.
By actuating clutch piston 79 in a conventional manner,
clutch hub 71 is clutched to drum 53 causing sun pinion 51, drum
53, hub 71 and sun shaft 43 to rotate as a unit. The input
shaft 21 rotates in the same direction as the carrier 29. The
35planetary pinions 37 and 39 want to rotate respective sun
pinions 45 and 51 at different rates but are unable to because
sun pinions 45 and 51 are coupled to sun shaft 48, therefor, the
sun gear shaft 43 will be rotated by the carrier 29 in the same
direction. By releasing clutch piston 79 and actuatin brake
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piston 69, sun pinion 51 is coupled to housing 11, thereby being
held stationary relative to housing 11. As the input shaft 21
turns carrier 29, planetary pinion 39 is forced to walk around
sun pinion 51 causing planetary pinion 37 to rctate sun gear
shaft 43 in the opposite direction from carrier 29.
It is observed that the rear cover 65 is secured to the
housing 11 by a plur~lity of bolts 87. Removing bolts 87 allows
cover 65 to be removed from the housing 61 bringing therewith
brake assembly 52 and clutch assembly 70, in addition to cun
shaft 43. It is noted that clutch drum 53 can slidably
disengage sun pinion 51 longitudinally. Should upon detachment
of rear cover 65 sun pinions 45 and 51 attempt to ride sun shaft
43, upon withdrawal of the recover approximately 3/4 to 1 inch
from the housing 11, a screwdriver or other such tool can be
inserted into the housing to restrain the sun pinions 45 and 51
within the planetary pinions 35.
The sun pinions 45 and 51, therefor, remain centered and
timed to planetary pinions 37 and 39, respectively.
It is observed that the clutch and brake assemblies 70 and
52 are maintained in the rear cover 65 in part riding on and
centered by the shaft 43, such that upon reinstallation of the
rear cover 65 to the housing 11 a mating fit is assured. In
particularly, shaft 43 is aligned to journey through sun pinion
51 to be splinably received by pinion 51 at 57. The clutch
assembly 70, brake assembly 52 and sun shaft 43 can simply be
slid back into place, and secured by the reattachment of bolts
87. Since sun pinions 48 and 51 are not disturbed, there is no
need to retime the planetary gear set.
It is further observed that the sun shaft 43 is supported in
a cantilevered fashion by the end cover 65 and that sun pinion
51 is spaced apart from sun shaft 43. This arrangement allows
the sun shaft 43 to experience a limited degree of float which
allows the sun shaft 41 portion splined to sun pinion 45 to seek
an approximating concentric alignment, eliminating the need for
elaborate shaft alignment procedures to prevent binding of the
sun pinlons.
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